Hossein Shahshahani (also known as Seyyed Hossein Shahshahani) () (1895 – 19 March 1962) was a prominent judge, scholar of Islamic Law and expert of historical documents and manuscripts of Iran.
Early life and education
Shahshahani was born in Isfahan, Iran in 1895 to a prominent and pious family where he received his preliminary and traditional education. His mother was from Allameh Majlesi family and his father was Seyyed Mohammad Sadr Shah Alaee, a religious scholar in Isfahan and a grandson of Shah Alaeddin Mohammad.

He moved to Tehran when he was 17 and subsequently traveled to Najaf where he pursued for seven years his education in advanced Islamic law and jurisprudence. He worked with several Islamic scholars, including Mirza Hossein Naini. This qualified him to be mujtahid who was recognized as an Islamic scholar competent in interpreting Islamic law independently.

Judicial career
Upon returning to Iran in 1921, initially he taught jurisprudence at the Advanced School of Trade (Madrasse-e Aali-e Tejarat) in Tehran. He was then invited by Ali-Akbar Davar, the founder of Iran's modern legal code, to take major responsibilities in the newly established Ministry of Justice of Iran.

His judiciary career took almost 30 years, during which time he served in various positions and moved up the hierarchy to the counselor of the Supreme Court (Divan-e Aali-e Keshvar). He was also the head of the Organization for Registration of Deeds and Properties.
Shahshahani was the permanent member from the Ministry of Justice in the commission that functioned as the inspector general appointed by Reza Shah. Toward the end of his career, in 1952 and 1953 (1331 and 1332), he served as the assistant Minister of Interior and the deputy Minister of Justice when he worked more closely with the Prime Minister, Dr. Mohammad Mosaddegh.
In recognition and appreciation of his superior service and dedication, he received several certificate and medals from the Shah. The medals included Order of the Crown.
Shahshahani had close relationships with most members of the Mosaddegh Cabinet. He was in charge of the Ministry of Justice when Mosaddegh traveled to The Hague to attend the International Court of Justice that was dealing with the nationalization of the Iranian Oil Industry. Shahshahani was also well respected by the clergy and the religious authorities. For example, he had written correspondence and personal meetings with Seyyed Hossein Tabatabaie Borujerdi in Qum.
Historical documents
Shahshahani was one of the few people who could read, understand and analyze the significance of rare and unique archival material and historical documents and deeds (firmans). They included firmans, manuscripts and calligraphy, hand written orders by kings and rulers, usually in cursive and writing of high historical and aesthetic value. He loved collecting such documents that were sometimes in poor shape. He spent countless hours to read, repair, understand, evaluate and at times frame them.
Shahshahani's valuable collection of such items which included more than 285 firmans and documents were given to the Reza Abbasi Museum in Tehran in 1978 (1357).
Work with scholars
Shahshahani gave close access to his friends and academic experts to study and review his collection for research, analysis and documentation purposes. He helped these people in reading and understanding the often difficult contents of these documents. Most of these scholars have kindly referenced him in their published works.
They include Agha Bozorg Tehrani, (the author of Azzari-a), Jalal al-Din Muhaddis, Dr. Manuchehr Sotudeh, Iraj Afshar, Ali Naghi Monzavi, the French scholar and author Jean Aubin, Dr. Horst Walther from Germany and references made by Louis Massignon.
Shahshahani helped Jean Aubin in his research efforts and made available to him some of his collection related to Aq Qoyunlu and Kara Qoyunlu periods. Jean Aubin's research results were published in Tehran in 1955 both in French and Persian languages as:
Jean Aubin, Archives persanes commentees.
Note sur quelques documents Aq Qoyunlu, dans Melanges Massignon, I, pp. 9–35 (sous presse). Note preliminaire sur les archives du Takya du Tchima-rud. (En preparation:) Deux recueils d'insha dédies au vizir timoride Ghiyathu-'d-Din Pir Ahmad Khwafi.
Selected Research Works
Shahshahani published the following works:





